This section provides background information related to the present disclosure which is not necessarily prior art.
Temperatures of operation for appliances, electronics, motors and other electrical devices typically have an optimum range. The temperature range where damage can occur to system components or where the device becomes a potential safety hazard is an important detection threshold. Various safety devices are capable of sensing such over-temperature thresholds. Certain safety devices are capable of sensing over-temperature conditions and interrupting electrical current, including electrical thermal fuses, which only operate in a narrow temperature range. For example, tin and lead alloys, indium and tin alloys, or other metal alloys that form a eutectic metal, are unsuitable for appliance, electronic, electrical and motor applications due to undesirably broad temperature response thresholds and/or detection temperatures that are outside the desired range of safety.
One type of device particularly suitable for over-temperature detection is an electrical current interruption safety device, known as a thermal cut-off device (TCO), which is capable of temperature detection and simultaneous interruption of current, when necessary. Such TCO devices are typically installed in an electrical application between the current source and electrical components, such that the TCO is capable of interrupting the circuit continuity in the event of a potentially harmful or dangerous over-temperature condition. TCOs are often designed to shut off the flow of electric current to the application in an irreversible manner, without the option of resetting the TCO current interrupting device. Certain appliances and applications require the use of robust over-temperature detection devices with high-holding temperatures exceeding the operating temperatures and/or holding temperatures of conventional TCO designs. Thus, in various aspects, the present disclosure provides TCO designs that are thermally stable and continue to exhibit dielectric properties after activation or current interruption, even at high temperatures.